SpudFiles

Well, got more questions like usual lmao. I’m thinking of making a PCP air shotgun for use on small tree-borne pests and all that. Breech loaded, single shot, and really simple mechanically. I’m just stuck on how to make some shells. Looking at normal air shotguns, it looks like they have a shell that uses two plugs with shot in between. That looks alright, but I don’t know how easy that is to make. Other types seem to contain the shot within a glass shell, acting as a burst disk. Definitely not something I can do. Feel free to correct me if I’m wrong on these assumptions btw.

So I’m just wondering what ideas you guys have towards making air shotgun shells. I have some designs of my own but I want to see if there’s better ideas out there. Probably going to go for a 3/4” bore and shooting with sub 600 PSI of pressure, if that is important.

I usually an aluminum foil cup/sabot for my basic air rifle.

Yeah, I usually use carefully folded up paper for my launcher as well. Works but definitely annoying, wish it was less finicky.

jacoblesann wrote:Well, got more questions like usual lmao. I’m thinking of making a PCP air shotgun for use on small tree-borne pests and all that.

First off, be aware of rule 2:

Discussion of shooting anything at any person and/or animal is prohibited, and may result in a permanent banning of your account.

So I’m just wondering what ideas you guys have towards making air shotgun shells. I have some designs of my own but I want to see if there’s better ideas out there. Probably going to go for a 3/4” bore and shooting with sub 600 PSI of pressure, if that is important.

Shotguns are inherently inefficient. Because of the way they operate, without a choke most of the projectiles are not going to hit your target, especially as range increases. Let's say your target needs 5 ft lbs of energy to be taken down, but at your chosen range only 20% of the shot is going to hit, which means that your shotgun needs to be generating 25 ft lbs on target.

You also need a considerable number of projectiles to guarantee a hit. With my Farco I did a test with 8 x 0.177" BBs at 50 feet/15 meters fired at a soda can, the BBs patterned nicely in a 1 foot square but not a single one hit the soda can. A similar test with the same target at the same range with 30 x #4 shot (about 1/8" diameter) resulting in a similar spread and only three hits on the can, only 10% of all the shot. In short, you're going to need a launcher that is more powerful than something equivalent capable of hitting the target with a single shot.

Packing all that power into a cartridge is going to be a challenge, especially if you don't have a lathe.

I’m sorry, I didn’t know that applied to animals as well. I’ll be sure not to do that from now on.

I’ve had similar findings. I’ve launched ~20 paintballs out of my 2” barrel and found them to pattern quite well- at like 10 feet. More than that, none of them ever did hit the Center, just as you described. The only way I got them to was to use the 3/4” barrel and load them in a straight line. Many of collapsed within the barrel (no fun to clean), but they did hit the Center. I suppose that works similar to a choke.

I can agree with the energy concerns, I’ve experienced those issues firsthand with my airsoft shotgun designs. I think I will stick with large, heavy ammo like lead balls.

I’m starting to realize the thought process behind the Nock Gun, lmao.

I think I'd just use normal 12 gauge shotgun wads and put 'em in a 3/4" bore air gun. Why reinvent the wheel?

That sounds like an alright plan, didn’t know these existed. Thanks for the tip.

Shotshell wads are split on the sides, and the roll crimp on the case is what holds everything in. Could put something in there to hold the shot, but it's not going to stand much handling.

Would use something more like the Crosman Trapmaster shells...plastic case and a cardboard disc/over wad to hold things in place. The shell stays with the gun, the shot and cardboard are fired.

Or a piece of tubing with a cardboard disc on either end.

There are some examples of a Crooked Barn shotshell breech online...relatively simple piece that used the Trapmaster shells.

Small shot is going to be the way to go, would use #7 1/2 or 9.

Gippeto wrote:Or a piece of tubing with a cardboard disc on either end.

That works great in the Farco, though it needs a couple of thick disks as a base to avoid losing power from blow-by.

Thats more along the lines of what I was thinking. Only complication there is to lock the shell within the barrel, but I’m sure it’s not much harder than upsetting the rear area with a hammer.

I was curious when I first learned of the wads within the shell, do these affect the shot upon firing? Specifically the one in front. I’ve never found much of an answer to that, I assume it breaks apart during the shot.

The Crosman shells have a rim on them. If I were doing this with a cartridge made of tubing, there would be a short recess in the barrel for the cartridge to seat/seal on (brass or aluminum tubing) and another on the bolt face...would not set it up to fully chamber the cartridge....extraction would otherwise be an issue needing resolving.

The wad offers some degree of cushion to the shot column during acceleration and prevents direct contact with the barrel...round pellets flying "nicer" than deformed ones. The wads open shortly after leaving the barrel, the petals of the wad peal back and the wad slows and separates from the shot in similar fashion to a sabot round separating. Usually find the plastic wads withing 20 yards or so.

That sounds alright. I’m imaging the bolt would have to push the rear wad slightly forward so that it can enter the inside of the shell, sealing it. Or something along those lines. I’ve decided to wait til I have myself a lathe before I attempt a PCP, but these ideas will help with my designs in general. Thank you for the explanation.

jacoblesann wrote:I’ve decided to wait til I have myself a lathe before I attempt a PCP, but these ideas will help with my designs in general. Thank you for the explanation.

Wise decision. I hate to say this but there's only so much you can do with epoxy.

For me, there’s only so much you can do with what you have laying around. Never had luck with epoxy, lol. Acraglas is good stuff, though.